The waters of the bay sparkled in the sunlight as we drove across the bridge to Oakland. Isabelle described the latest session of the European parliamentary committee into adai rights. A draft proposal granting personhood to any system containing and acting upon a significant amount of the information content of human DNA had been gaining support; it was a tricky concept to define rigorously, but most of the objections were Pythonesque rather than practical. "Is the Human Proteomic Database a person?

Is the Harvard Reference Physiological Simulation a person?" The HRPS modeled the brain solely in terms of what it removed from, and released into, the bloodstream; there was n.o.body home inside the simulation, quietly going mad.

Late in the evening, when the girls were upstairs, Isabelle began gently grilling us. I tried not to grit my teeth too much. I certainly didn't blame her for taking her responsibilities seriously; if, in spite of the selection process, we had turned out to be monsters, criminal law would have offered no remedies. Our obligations under the licensing contract were Helen's sole guarantee of humane treatment.

"She's getting good marks this year," Isabelle noted. "She must be settling in."

"She is," Francine replied. Helen was not ent.i.tled to a government-funded education, and most private schools had either been openly hostile, or had come up with such excuses as insurance policies that would have cla.s.sified her as hazardous machinery. (Isabelle had reached a compromise with the airlines: Sophie had to be powered down, appearing to sleep during flights, but was not required to be shackled or stowed in the cargo hold.) The first community school we'd tried had not worked out, but we'd eventually found one close to the Berkeley campus where every parent involved was happy with the idea of Helen's presence. This had saved her from the prospect of joining a net-based school; they weren't so bad, but they were intended for children isolated by geography or illness, circ.u.mstances that could not be overcome by other means. Isabelle bid us good night with no complaints or advice; Francine and I sat by the fire for a while, just smiling at each other. It was nice to have a blemish-free report for once.

The next morning, my alarm went off an hour early. I lay motionless for a while, waiting for my head to clear, before asking my knowledge miner why it had woken me.

It seemed Isabelle's visit had been beaten up into a major story in some east coast news bulletins. A number of vocal members of Congress had been following the debate in Europe, and they didn't like the way it was heading. Isabelle, they declared, had sneaked into the country as an agitator. In fact, she'd offered to testify to Congress any time they wanted to hear about her work, but they'd never taken her up on it.

It wasn't clear whether it was reporters or anti-adai activists who'd obtained her itinerary and done some digging, but all the details had now been splashed around the country, and protesters were already gathering outside Helen's school. We'd faced media packs, cranks, and activists before, but the images the knowledge miner showed me were disturbing; it was five a.m. and the crowd had already encircled the school. I had a flashback to some news footage I'd seen in my teens, of young schoolgirls in Northern Ireland running the gauntlet of a protest by the opposing political faction; I could no longer remember who had been Catholic and who had been Protestant.

I woke Francine and explained the situation.

"We could just keep her home," I suggested.

Francine looked torn, but she finally agreed. "It will probably all blow over when Isabelle flies out on Sunday. One day off school isn't exactly capitulating to the mob."

At breakfast, I broke the news to Helen.

"I'm not staying home," she said.

"Why not? Don't you want to hang out with Sophie?"

Helen was amused. " 'Hang out'? Is that what the hippies used to say?" In her personal chronology of San Francisco, anything from before her birth belonged to the world portrayed in the tourist museums of Haight-Ashbury.

"Gossip. Listen to music. Interact socially in whatever manner you find agreeable."

She contemplated this last, open-ended definition. "Shop?"

"I don't see why not." There was no crowd outside the house, and though we were probably being watched, the protest was too large to be a moveable feast. Perhaps all the other parents would keep their children home, leaving the various placard wavers to fight among themselves.

Helen reconsidered. "No. We're doing that on Sat.u.r.day. I want to go to school."

I glanced at Francine. Helen added, "It's not as if they can hurt me. I'm backed up."

Francine said, "It's not pleasant being shouted at. Insulted. Pushed around."

"I don't think it's going to be pleasant," Helen replied scornfully. "But I'm not going to let them tell me what to do."

To date, a handful of strangers had got close enough to yell abuse at her, and some of the children at her first school had been about as violent as (ordinary, drug-free, non-psychotic) nine-year-old bullies could be, but she'd never faced anything like this. I showed her the live news feed. She was not swayed.

Francine and I retreated to the living room to confer.

I said, "I don't think it's a good idea." On top of everything else, I was beginning to suffer from a paranoid fear that Isabelle would blame us for the whole situation. Less fancifully, she could easily disapprove of us exposing Helen to the protesters. Even if that was not enough for her to terminate the license immediately, eroding her confidence in us could lead to that fate, eventually.

Francine thought for a while. "If we both go with her, both walk beside her, what are they going to do? If they lay a finger on us, it's a.s.sault. If they try to drag her away from us, it's theft."

"Yes, but whatever they do, she gets to hear all the poison they spew out."

"She watches the news, Ben. She's heard it all before."

"Oh, s.h.i.t." Isabelle and Sophie had come down to breakfast; I could hear Helen calmly filling them in about her plans.

Francine said, "Forget about pleasing Isabelle. If Helen wants to do this, knowing what it entails, andwe can keep her safe, then we should respect her decision."

I felt a sting of anger at the unspoken implication: having gone to such lengths to enable her to make meaningful choices, I'd be a hypocrite to stand in her way. Knowing what it entails? She was nine-and-a-half years old.

I admired her courage, though, and I did believe that we could protect her.

I said, "All right. You call the other parents. I'll inform the police."

The moment we left the car, we were spotted. Shouts rang out, and a tide of angry people flowed toward us.

I glanced down at Helen and tightened my grip on her. "Don't let go of our hands."

She smiled at me indulgently, as if I was warning her about something trivial, like broken gla.s.s on the beach. "I'll be all right, Dad." She flinched as the crowd closed in, and then there were bodies pushing against us from every side, people jabbering in our faces, spittle flying. Francine and I turned to face each other, making something of a protective cage and a wedge through the adult legs. Frightening as it was to be submerged, I was glad my daughter wasn't at eye level with these people.

"Satan moves her! Satan is inside her! Out, Jezebel spirit!" A young woman in a high-collared lilac dress pressed her body against me and started praying in tongues.

"G.o.del's theorem proves that the non-computible, nonlinear world behind the quantum collapse is a manifest expression of Buddha-nature," a neatly dressed youth intoned earnestly, establishing with admirable economy that he had no idea what any of these terms meant. "Ergo, there can be no soul in the machine."

"Cyber nano quantum. Cyber nano quantum. Cyber nano quantum." That chant came from one of our would-be "supporters," a middle-aged man in Lycra cycling shorts who was forcefully groping down between us, trying to lay his hand on Helen's head and leave a few flakes of dead skin behind; according to cult doctrine, this would enable her to resurrect him when she got around to establishing the Omega Point. I blocked his way as firmly as I could without actually a.s.saulting him, and he wailed like a pilgrim denied admission to Lourdes.

"Think you're going to live forever, Tinkerbell?" A leering old man with a matted beard poked his head out in front of us, and spat straight into Helen's face.

"a.s.shole!" Francine shouted. She pulled out a handkerchief and started mopping the phlegm away. I crouched down and stretched my free arm around them. Helen was grimacing with disgust as Francine dabbed at her, but she wasn't crying.

I said, "Do you want to go back to the car?"

"No."

"Are you sure?"

Helen screwed up her face in an expression of irritation. "Why do you always ask me that? Am I sure? Am I sure? You're the one who sounds like a computer."

"I'm sorry." I squeezed her hand.

We plowed on through the crowd. The core of the protesters turned out to be both saner and more civilized than the lunatics who'd got to us first; as we neared the school gates, people struggled to make room to let us through uninjured, at the same time as they shouted slogans for the cameras. "Healthcare for all, not just the rich!" I couldn't argue with that sentiment, though adai were just one of a thousand ways the wealthy could spare their children from disease, and in fact they were among the cheapest: the total cost in prosthetic bodies up to adult size came to less than the median lifetime expenditure on healthcare in the U.S. Banning adai wouldn't end the disparity between rich and poor, but I could understand why some people considered it the ultimate act of selfishness to create a child who could live forever. They probably never wondered about the fertility rates and resource use of their own descendants over the next few thousand years.

We pa.s.sed through the gates, into a world of s.p.a.ce and silence; any protester who trespa.s.sed here could be arrested immediately, and apparently none of them were sufficiently dedicated to Gandhian principles to seek out that fate. Inside the entrance hall, I squatted down and put my arms around Helen. "Are you OK?"

"Yes."

"I'm really proud of you."

"You're shaking." She was right; my whole body was trembling slightly. It was more than the crush and the confrontation, and the sense of relief that we'd come through unscathed. Relief was never absolute for me; I could never quite erase the images of other possibilities at the back of my mind.

One of the teachers, Carmela Pena, approached us, looking stoical; when they'd agreed to take Helen, all the staff and parents had known that a day like this would come.

Helen said, "I'll be OK now." She kissed me on the cheek, then did the same to Francine. "I'm all right," she insisted. "You can go."

Carmela said, "We've got 60 percent of the kids coming. Not bad, considering."

Helen walked down the corridor, turning once to wave at us impatiently.

I said, "No, not bad."

A group of journalists cornered the five of us during the girls' shopping trip the next day, but media organizations had grown wary of lawsuits, and after Isabelle reminded them that she was presently enjoying "the ordinary liberties of every private citizen"-a quote from a recent eight-figure judgment against Celebrity Stalker-they left us in peace.

The night after Isabelle and Sophie flew out, I went in to Helen's room to kiss her good night. As I turned to leave, she said, "What's a Qusp?"

"It's a kind of computer. Where did you hear about that?"

"On the net. It said I had a Qusp, but Sophie didn't."

Francine and I had made no firm decision as to what we'd tell her, and when. I said, "That's right, but it's nothing to worry about. It just means you're a little bit different from her."

Helen scowled. "I don't want to be different from Sophie."

"Everyone's different from everyone else," I said glibly. "Having a Qusp is just like...a car having a different kind of engine. It can still go to all the same places." Just not all of them at once. "You can both still do whatever you like. You can be as much like Sophie as you want." That wasn't entirely dishonest; the crucial difference could always be erased, simply by disabling the Qusp's shielding.

"I want to be the same," Helen insisted. "Next time I grow, why can't you give me what Sophie's got, instead?"

"What you have is newer. It's better."

"No one else has got it. Not just Sophie; none of the others." Helen knew she'd nailed me: if it was newer and better, why didn't the younger adai have it too?

I said, "It's complicated. You'd better go to sleep now; we'll talk about it later." I fussed with the blankets, and she stared at me resentfully.

I went downstairs and recounted the conversation to Francine. "What do you think?" I asked her. "Is it time?"

"Maybe it is," she said.

"I wanted to wait until she was old enough to understand the MWI ."

Francine considered this. "Understand it how well, though? She's not going to be juggling density matrices any time soon. And if we make it a big secret, she's just going to get half-baked versions from other sources."

I flopped onto the couch. "This is going to be hard." I'd rehea.r.s.ed the moment a thousand times, but in my imagination Helen had always been older, and there'd been hundreds of other adai with Qusps. In reality, no one had followed the trail we'd blazed. The evidence for the MWI had grown steadily stronger, but for most people it was still easy to ignore. Ever more sophisticated versions of rats running mazes just looked like elaborate computer games. You couldn't travel from branch to branch yourself, you couldn't spy on your parallel alter egos-and such feats would probably never be possible. "How do you tell a nine-year-old girl that she's the only sentient being on the planet who can make a decision, and stick to it?" Francine smiled. "Not in those words, for a start."

"No." I put my arm around her. We were about to enter a minefield-and we couldn't help diffusing out across the perilous ground-but at least we had each other's judgment to keep us in check, to rein us in a little.

I said, "We'll work it out. We'll find the right way."

2050.

Around four in the morning, I gave in to the cravings and lit my first cigarette in a month.

As I drew the warm smoke into my lungs, my teeth started chattering, as if the contrast had forced me to notice how cold the rest of my body had become. The red glow of the tip was the brightest thing in sight, but if there was a camera trained on me it would be infrared, so I'd been blazing away like a bonfire, anyway. As the smoke came back up I spluttered like a cat choking on a fur ball; the first one was always like that. I'd taken up the habit at the surreal age of 60, and even after five years on and off, my respiratory tract couldn't quite believe its bad luck.

For five hours, I'd been crouched in the mud at the edge of Lake Pontchartrain, a couple of kilometers west of the soggy ruins of New Orleans. Watching the barge, waiting for someone to come home. I'd been tempted to swim out and take a look around, but my aide sketched a bright red moat of domestic radar on the surface of the water, and offered no guarantee that I'd remain undetected even if I stayed outside the perimeter.

I'd called Francine the night before. It had been a short, tense conversation.

"I'm in Louisiana. I think I've got a lead."

"Yeah?"

"I'll let you know how it turns out."

"You do that."

I hadn't seen her in the flesh for almost two years. After facing too many dead ends together, we'd split up to cover more ground: Francine had searched from New York to Seattle; I'd taken the south. As the months had slipped away, her determination to put every emotional reaction aside for the sake of the task had gradually eroded. One night, I was sure, grief had overtaken her, alone in some soulless motel room-and it made no difference that the same thing had happened to me, a month later or a week before. Because we had not experienced it together, it was not a shared pain, a burden made lighter.

After 47 years, though we now had a single purpose as never before, we were starting to come adrift.

I'd learned about Jake Holder in Baton Rouge, triangulating on rumors and fifth-hand reports of barroom boasts. The boasts were usually empty; a prosthetic body equipped with software dumber than a microwave could make an infinitely pliable slave, but if the only way to salvage any trace of dignity when your buddies discovered that you owned the high-tech equivalent of a blowup doll was to imply that there was somebody home inside, apparently a lot of men leaped at the chance.

Holder looked like something worse. I'd bought his lifetime purchasing records, and there'd been a steady stream of cyber-fetish p.o.r.n over a period of two decades. Hardcore and pretentious; half the t.i.tles contained the word "manifesto." But the flow had stopped, about three months ago. The rumors were, he'd found something better.

I finished the cigarette, and slapped my arms to get the circulation going. She would not be on the barge. For all I knew, she'd heard the news from Brussels and was already halfway to Europe. That would be a difficult journey to make on her own, but there was no reason to believe that she didn't have loyal, trustworthy friends to a.s.sist her. I had too many out-of-date memories burned into my skull: all the blazing, pointless rows, all the petty crimes, all the self-mutilation. Whatever had happened, whatever she'd been through, she was no longer the angry 15-year-old who'd left for school one Friday and never come back.

By the time she'd hit 13, we were arguing about everything. Her body had no need for the hormonal flood of p.u.b.erty, but the software had ground on relentlessly, simulating all the neuroendocrine effects.

Sometimes it had seemed like an act of torture to put her through that-instead of hunting for some magic shortcut to maturity-but the cardinal rule had been never to tinker, never to intervene, just to aim for themost faithful simulation possible of ordinary human development.

Whatever we'd fought about, she'd always known how to shut me up. "I'm just a thing to you! An instrument! Daddy's little silver bullet!" I didn't care who she was, or what she wanted; I'd fashioned her solely to slay my own fears. (I'd lie awake afterward, rehearsing lame counterarguments. Other children were born for infinitely baser motives: to work the fields, to sit in boardrooms, to banish ennui, to save failing marriages.) In her eyes, the Qusp itself wasn't good or bad-and she turned down all my offers to disable the shielding; that would have let me off the hook too easily. But I'd made her a freak for my own selfish reasons; I'd set her apart even from the other adai, purely to grant myself a certain kind of comfort. "You wanted to give birth to a singleton? Why didn't you just shoot yourself in the head every time you made a bad decision?"

When she went missing, we were afraid she'd been s.n.a.t.c.hed from the street. But in her room, we'd found an envelope with the locator beacon she'd dug out of her body, and a note that read: Don't look for me. I'm never coming back.

I heard the tires of a heavy vehicle squelching along the muddy track to my left. I hunkered lower, making sure I was hidden in the undergrowth. As the truck came to a halt with a faint metallic shudder, the barge disgorged an unmanned motorboat. My aide had captured the data streams exchanged, one specific challenge and response, but it had no clue how to crack the general case and mimic the barge's owner.

Two men climbed out of the truck. One was Jake Holder; I couldn't make out his face in the starlight, but I'd sat within a few meters of him in diners and bars in Baton Rouge, and my aide knew his somatic signature: the electromagnetic radiation from his nervous system and implants; his body's capacitative and inductive responses to small shifts in the ambient fields; the faint gamma-ray spectrum of his unavoidable, idiosyncratic load of radioisotopes, natural and Chern.o.bylesque.

I did not know who his companion was, but I soon got the general idea.

"One thousand now," Holder said. "One thousand when you get back." His silhouette gestured at the waiting motor-boat.

The other man was suspicious. "How do I know it will be what you say it is?"

"Don't call her 'it'," Holder complained. "She's not an object. She's my Lilith, my Lo-li-ta, my luscious clockwork succubus." For one hopeful moment, I pictured the customer snickering at this overheated sales pitch and coming to his senses; brothels in Baton Rouge openly advertised machine s.e.x, with skilled human puppeteers, for a fraction of the price. Whatever he imagined the special thrill of a genuine adai to be, he had no way of knowing that Holder didn't have an accomplice controlling the body on the barge in exactly the same fashion. He might even be paying 2,000 dollars for a puppet job from Holder himself.